The present invention generally relates to video signal recording and/or reproducing apparatuses having a function for temporarily stopping recording, and more particularly to a video signal recording and/or reproducing apparatus designed to cause a tape to travel in a reverse direction for a predetermined time period and then to turn the power OFF in a state where the tape is loaded along a predetermined tape path when a power source switch is turned OFF during a recording mode.
Generally, in a video signal recording and/or reproducing apparatus, and particularly in a video signal recording and/or reproducing apparatus which records a picked-up video signal from a television camera onto a tape, the apparatus is frequently operated in a manner such that the recording operation is temporarily stopped during the recording and the recording operation is resumed thereafter. It is common to operate the apparatus in this manner when using a portable television camera and recording the picked-up video signal onto the tape by a portable recording and/or reproducing apparatus.
When the power source switch is turned OFF in order to temporarily stop the recording operation while recording the picked-up video signal from the television camera related to a certain picture, rotary heads stop rotating and the tape travel stops. Thus, the tape, which was drawn out of a cassette and loaded along a predetermined tape path within the apparatus upon starting of the recording, is drawn back into the cassette and unloaded. Hence, if the mode of the apparatus is set to the recording mode and the tape is drawn out of the cassette and loaded along the predetermined tape path so as to resume the recording of the picked-up video signal related to another picture, the tape position with respect to the heads before the tape unloading operation does not accurately coincide with the tape position after the tape is loaded again to resume the recording operation. Accordingly, if the recording operation is resumed after carrying out the tape unloading and loading operations as described above, an unrecorded part may be formed on the tape between a previously recorded part and a part which is newly recorded, or an overlapping part may be formed on the tape if the recording is resumed from a part overlapping the previously recorded part.
In order to eliminate the unwanted deviation in the tape position introduced during the tape unloading and loading operations, the tape may be maintained in the loaded state along the predetermined tape path during predetermined modes, that is, measures may be taken to prevent the tape from being unloaded during the predetermined modes.
However, even if measures are taken to maintain the tape in the loaded state, the tape travel does not stop immediately as an operation is carried out to temporarily stop the tape travel, due to inertia of a tape feeding system. As a result, the tape stops after traveling over a certain distance. Further, when resuming the tape travel so as to resume the recording, it will take a certain time period for the tape traveling speed to reach a predetermined tape travel speed. Accordingly, if the recording is resumed by simply resuming the tape travel from a position where the tape stopped, stable recording cannot be carried out during the initial period of the resumed recording. Thus, if a tape recorded in this manner is reproduced, the servo operation becomes unstable at a recording interstice, that is, at the part between where the recording is temporarily stopped and where it is resumed thereafter, and there will be a problem in that the reproduced picture will become distorted. In addition, if the recording is resumed after the tape travel is resumed and the tape travel speed has reached the predetermined tape travel speed, an unrecorded part will be formed on the tape between the previously recorded part and the part which is next recorded, and the reproduced picture will become unsatisfactory for viewing.
In order to prevent such problems from being introduced, it is necessary to automatically rotate a supply reel in a tape take-up direction and rewind the tape by a predetermined quantity before stopping the tape, when temporarily stopping the recording operation. By taking such a measure, the tape travel speed will reach the predetermined tape travel speed over a distance corresponding to the rewound quantity of tape, upon resumption of the recording. Moreover, the recording can be carried out satisfactorily in continuity with the previously recorded part, when the recording is resumed after the tape travel speed has reached the predetermined tape travel speed.
However, when the recording operation is temporarily stopped during the recording, the rotary heads continue to rotate although the tape travel is stopped in the state where the tape is loaded. This is because if the rotary heads also stop rotating, it will take a certain time period (three seconds, for example) for the rotary heads to reach a predetermined rotational speed from the time when the rotary heads begin to rotate, and the beginning of the signal to be recorded will not be recorded.
Accordingly, if the operator forgets to set the mode of the apparatus to a stop mode after temporarily stopping the recording even though the operator no longer intends to resume the recording, or if the apparatus is set to a recording pause mode but the recording of the picked-up signal related to the next picture which is picked up will not be resumed for a long period of time, the apparatus will remain in a recording pause mode during a long period of time. That is, the tape will remain in the temporarily stopped state and the rotary heads will continue to trace over the same portion of the tape during that long period of time. Hence, there will be problems in that the tape will become worn due to friction, magnetic particles will adhere onto the magnetic heads, and the power consumption will become large. Therefore, the conventional apparatus was designed to automatically release the apparatus from the pause mode, unload the tape into the cassette, and turn the power source OFF, if the apparatus is left in the pause mode for longer than a predetermined time period (five minutes, for example).
However, the apparatus may be released from the pause mode even though the operator intended to resume the recording just because the apparatus was left in the pause mode for over five minutes. In such a case, when the mode of the apparatus is set to the recording mode so as to resume the recording, the tape is again drawn out of the cassette and loaded along the predetermined tape path within the apparatus. In this state, the tape position with respect to the heads before the unloading and the tape position after the loading differ, and the previously described problems accompanied by such deviation in the tape position are introduced as a result.
Further, when automatically rewinding the predetermined quantity of tape when temporarily stopping the recording operation as described before, the mode of the apparatus is set to the reproducing mode while the predetermined quantity of tape is being rewound, in order to display the contents of the video signal recorded immediately before the recording is temporarily stopped on a monitoring screen in a viewfinder of the television camera. In this state, when the mode of the apparatus is set simultaneously to the reproducing mode and the recording pause mode, noise will appear in the reproduced picture for a short period of time and the reproduced picture becomes unsatisfactory because no signal is recorded for the portion of the tape which overran due to inertia.